The 55 competing nations have been placed into four tiers based on their current UEFA ranking and each tier is split into four leagues - A, B, C and D - made up of three or four teams. Between September and November the teams in each league will play each other home and away.
The team finishing top of each group is promoted to a higher league and the team finishing bottom of each group is relegated to a lower league, except in the lowest tier (D).
The four teams who win their respective League A groups (the bit England are involved in) will qualify for the knockout finals in June 2019 - semi-finals, final and third-place play-off - to decide the Nations League winner. One of those four teams will act as the hosts of the event - with a decision on that to be taken in December.
England will play in the top tier (League A) and have been drawn to play World Cup finalists Croatia, plus Spain, in Group Four. England host Spain on Saturday (September 8) at Wembley.
Wales and the Republic of Ireland will play in the second tier (League B) and have both been drawn in Group Four alongside Denmark. Wales host the Republic on Thursday (September 6) and play in Aarhus on Monday, September 10.
Northern Ireland will also play in League B and have been drawn to face Bosnia-Herzegovina and Austria in Group Three. Northern Ireland play Bosnia on Saturday (September 8) at Windsor Park.
Scotland are in the third tier (League C) and they have been drawn to play Israel and Albania in Group One. Scotland play Albania at Hampden Park on Monday, September 10.
Yes. The Euro 2020 qualification draw takes place in Dublin in December with all the matches due to be played between March and November 2019.
The top two teams from 10 groups will automatically qualify for the finals. That will account for 20 of the finalists. The final four places are where the Nations League comes in again.
Yes. The four group winners from each league - A, B, C and D, so 16 teams in all - will play off in March 2020 in a bid to secure one of the four remaining places. The format will be one-off play-off semi-finals, followed by a final, per league, with the winning team from each of leagues A, B, C and D taking the last four spots at the Euros.
If a country has already qualified by the conventional route, their place will go to the next highest-ranked team from their respective Nations League tier.
League A draw
Group 1: Germany, France, Netherlands
Group 2: Belgium, Switzerland, Iceland
Group 3: Portugal, Italy, Poland
Group 4: Spain, England, Croatia
League B draw
Group 1: Slovakia, Ukraine, Czech Republic
Group 2: Russia, Sweden, Turkey
Group 3: Austria, Bosnia & Herzegovina, Northern Ireland
Group 4: Wales, Republic of Ireland, Denmark
League C draw
Group 1: Scotland, Albania, Israel
Group 2: Hungary, Greece, Finland, Estonia
Group 3: Slovenia, Norway, Bulgaria, Cyprus
Group 4: Romania, Serbia, Montenegro, Lithuania
League D draw
Group 1: Georgia, Latvia, Kazakhstan, Andorra
Group 2: Belarus, Luxembourg, Moldova, San Marino
Group 3: Azerbaijan, Faro Islands, Malta, Kosovo
Group 4: FYR Macedonia, Armenia, Lichtenstein, Gibraltar